Telephone system



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Patented June 2,. 1925.

UNITED STATES PA NT oFFic-s.

Viv. I

wanna PINELL,' or ennnm-smmnnssrnnr, GERMANY, ASSIGNOB T smunns &

nALsxn AKTIENGESELLSCHAFT, or smmsnss'rnnnnnan BERLIN, GERMANY.

Application and Aprilli, 1922.- Serial an. $49,957.

. To all whom it may concern:

Be it known that I, Wmak PINnLL, a

German citizen, and a resident of Berlin- Siemens'stadt, Halske Steg. 4, Germany, have invented certain new and useful Improvements in Telephone Systems, of which the following is a specification.-

The present invention relates to circuit arrangement for automatic or semi-automatic telephone systems in which connections can be set up over several exchanges, and in which the im ulse transmitting devices can be centralized in one or moreexchanges.

In large telephone systems comprising several exchanges it is desirable to centralize the subscribers lines as much as possible, while at the same time itis desirable to economize trunk lines. For this purpose circuit arrangements have already beenproposed where!) a connection is set up between two subscribers of a local exchange by first setting numerical switches in another exchange and then effecting a switching operation, by which these numerical switches are released and the speaking connection is set up only over switches in the local exchange.-

The invention therefore concerns automatic or semi-automatic telephone systems,

pulse storing and translating devices are provided at the exchanges. A feature of the invention consists of the provision of switching devices so arranged that, when a subscriber makes a local'call, the first numerical switches at another exchange, that have been set by the impulse sender, are released after numerical switches in the local exchange have been connected up; while'the release of the trunk line between the exchange of the calling subscriber and the exchange containing the sender is etfected only after all the registers have been set.

Several methods of carr ing out the invention are shown in the d i'awings:

Figure 1 diagrammatically shows a telephone area.

Figure 221ml 2 show the circuit of a semiautomatic system.

Figure 3 shows diagrammatically an arrangement for an automatictele hone system, using selectors, each ofv w ich have twenty di erent groups of bank contacts.

in which numerical impulse sending or im-- Figures 4 and 4 represent the circuit of' a an automatic telephone-installation wherein after all the numerical switches atthe local exchange have been set, the calling line isv switched over from the trunk line to the numerical switches at the local exchan e. In the example shown in Figure 5 t e switching over of the calling line takes placeimmediately after a numerical switch has been set.

In Figure 1 a telephone area with four l i I large exchanges is shown. These exchanges A, B, C and D contain all the selectors necessary for establishing a" connection namely first, second and third group selectors and final selectors. Furthermore they contain the pre-selecting devices of the subscribers directly connected to these ex: changes,and, in the case of semi-automatic systems, the service selectors used for con:

nectin u the o erators osition as well;

as the impulse sender coup ed to the operators position, whereas in automatic systerms the impulse translators take the place of the operatorsposition. With these large exchanges A,.B, (J, D small exchanges (satellites) AU, BU, CU

. containing only a few of the switches are associated several required for setting up a connection. The

small excha e AU is directly connected by trunk lines L to the exchange A. The small exchanges BU BU", BUm are directl connected to the exchange B by other trun lines. The other sub-exchanges are similarly connected to their respective main exchanges.

The switches in the exchanges AU A and B are shown diagrammatica 9 0] 1y. It will be I assumed that the subscriber 35348 belonging to the satellite A-U, wishes to speak to the subscriber 23619 of the exchange B. When he originates the call, the. non-numerical switches I VW, II VW connect him to a trunk line VL extending from AU to A. This line is at the exchange A (in a semiautomatic system), connected by a service selector DW with an operators position. The operator answers the call and sets the first group'selector IGW, which has been connected up by the secondary selector ZW, on a connecting line VL leading to the exchangeB. The second sele'ctors'II GW, III GW, as well as the and-third group;

' the relay 1, closes the following off norm'al contact 15, battery.

final selector LIV at the exchange B are then .set and the subscribers 35348 and 23619 can converse.

If, however, the subscriber 35348 wishes to be connected with the subscriber- 35637 who is connected to the same exchange a switching eration takes place in the exchange A, a ter the transmission of impulses 'for settin the first and second roup selectors l div, II GW, whereby a'tlnrd group selector III GV is connected up at the exchang- AU,. It is operated over the trunk line VL, The final selector is also operated over the trunk line VL The first and second group selectors I (ilV and II GIV in the exchange A are available for other calls as soon as the third group selector III GW has been connected'up, but the trunk line VL remains connected until all the trains of impulses have been transmitted.

When all the selectors have been operated conversation between the subscribers 35348 and 3563? takes place over the first and second pre-selectors I VW, II VW, the trunk line VL, third group selector III GIV and the final selector LIV.

The switching operations will now be considered in detail with reference to Figures 2 and 2. When the subscriber 35348 calls, R is energized and at its contact circuit for the rotary magnet D: battery, contacts 1, d, rotary magnet D, contact 4, earth. The first prer selector I V'W seeks a free second )reselector II VW and when it has found it, the following test circuit is completed: Earth, contact 2, windings I and II of relay T, test wiper 0 of the first pre-selector I VIV. contact 3, relay R battery. Relay T at contact 4 opens the circuit of the rotary magnet D and short circuits at contact 5 its high resistance winding I, whereby the second pre-selcctor II VIV taken into use is marked engaged. Furthermore at contacts 6 and 7 it disconnects the calling relay and at 8 and 9 cuts through the operating leads. Relay R at the second pre-selector. II V IV is operated. It closes at contact 10 the circuit of the rotary magnet D and prepares at 11 the circuit for the test relay T If the second pre-selcctor II VWV finds a free trunk line VL leading to the exchange A, the following test circuit is closed: Earth, contact 11, windings l and II of relay T contact 12, test wiper 0, test conductor of the second pre-selector II VVV of the trunk line VL,, relay C, resistance 13, contact 14, Relay T at contact 16 opens the circuit of the rotary magnet D,, at contact 3 disconnects relay R and at contact ,17 switches through the test lead from the first re-selector LVIV to the trunk lineVL so tiat its high resistance winding I is dcenergized. At contacts and the auxiliary switch MLW.

18 and 19 the speaking leads a, b are switched through. The bridged relay A responds at the connecting line VL in at contact 20 the circuit for the slow acting release relay V. Relay O is locked over [contacts 21 and 22. At contact 23 a circuit is closed over resistances 24 and 25' for the relays C and C connected to the 0 lead in exchange nected in series only relay 0 can operate. It closes its contacts 26, 27, '28, 29 and 30. The closing of contact 26 connects u rotar magnet D of the service selector DV whic is energizedas follows: Earth, contacts 31, 26, 32, rotary magnet 1),, contact 333, battery. If the service selector DW finds a free operators position, the test relay T is energized as follows: Earth, contacts 34, 27, windings I and II of the test relay T wiper of the service selector DIV, resistance 36, contact 2' battery. Relay cutting A. Of the two relays con- T responds and at contact 32 opens the circuit of the rotary magnet D at contact 37 it short circuits its high resistance winding I, at contact 38 it prepares the circuit for relay E which is to operate later on, and at contacts 39 and 40 connects the calling line to the operators instrument.

The secondary selector ZW is operated at the same time as the service selector DW', and its rotary magnet D is energized as follows: Earth, contacts 29, 41, 42, rotary ma net D contact 43, battery. If the secon ary selector ZW finds a free first group selector LGVV the following circuit is completed: Earth, contacts 44, 30, windings I and II of relay P, test wiper of the secondary selector ZW, relay C ofi normal contact 46, battery.

If the calling subscriber requires connection with a subscriber belonging to his own exchange, the operator presses on the keys corresponding to the required number and sends out impulses. The operators instrument is disconnected at contacts 47 and 43, and atrontact 49 the impulse contact 50 is connected to the a. lead. Since the impulse contact 50 is closed, the relays A and A are energized. Relay A at contact 51 connects up relay V and relay A, at contact 52 connects up the relay V The 0 eration of the first and second group se ectors LGIV, II.GIV in the exchange A will now be described, and then an explanation will be given of the effect produced by the trains of impulses on the devices in the exchange of the calling subscriber.

Relay V in the first group selector I. GW completes at contact 652 a lockingcircuit for relay G which was prepared at contact 53. IVhen impulses are transmitted for raising the first group selector I GIV to the required level, the lifting magnet H is energized as follows: Earth, contacts 54, 55, relay V lifting magnet H, shaft contact 56, battery. During the impulse transmission the "relay V,,remains energized be cause its armature is slow. to release. When the. relay A remains energized at the termination of the train of impulses, relay V is deenergized and closes the following circuit for the rotary magnet 1),: Earth, contact; 57, 58,- rotary magnet 1),, contact 59, oil normal contact (it) (closed at the first lilting step of the selector) battery. The

first group selector I ,G-VV hunts-for a free selector II'GIV. The impulse relay A is disconnected at contact 64, the speaking leads (I, b are switched through at contacts and 66 and at contact 67 the locking C11- fcuit for relay C is maintained which would otherwise be opened at contact 652, when the relay V, is deeuergized. The second group selector II GVV is operated in known manner.

The impulses for setting thefirst and second group selectors I GIV and II GIV cause circuit changes at the exchange AU 'of'the calling subscriber 35348 and these will now be described. The rotary magnet D of the switch MLIV is energized by the first impulse of the first train of impulses as follows: Battery, contact 263, rotary magnet D contact 264, relay V zero contact 265, contact 266, impulse contact 267, earth. Relay-V responds and closes contact 68 so that the circuit for the rotary magnet remains closed even after the wiper has left the contact 265. At the end of this train, which is composedof three impulses, relay V falls back and the auxiliary relay O is energized as follows: Earth, contact 69 of rela V right-hand wiper of MLW, contact T1, relay 0, oil normal contact 72 of the switch MLIV, battery. Relay 0 connects itself at 73 to a locking circuit, which is only dependent on the off normal contact 72, and also closes the contacts 74 and 75. The first impulse of the second impulse train which operates the second group selector in the exchange A, also energizes magnet D and relay V over contact 74 of relay 0 and bank contact 7 6 of the switch MLIV. Relay V is again energized and closes the contact 68 which is then parallel to contacts T l and 76 through contact 266, so that the succeeding impulses of the second train can control the magnet D, even after the switch wiper has left contact 7 6.

and of C in the first group'selector I GVV.

- are thereb The second train of impulses is composed of five impulses. Another auxiliary relay N is connected over contact .75 to the eighth contact of the switch MLIV. 'lhis'rclay energized as soon as relay V is deenergized. It opens its contact 77 and over contactv 78-connects itself in a lockingcircuit, which is only dependent on the oil normal contact 72 of the switch MLIV. The. relay N furthermore ,short circuits resistance 24 at contact 79, .so that the marginal relay C in exchange A can respond. The latter by opening its "contact 44- ope'ns the circuit of relay P at the secondary selector ZIV 80" The relay P opens contacts 60 and 61in the speaking leads which were closed byjit when group selector I GW was set. Relay C in the first group selector I GIV opens its contact 61, thereby opening the circuit of relay P at the first group selector I GIV and C, at the second grou selector II GW. After relay P,- has been re eased, the release magnet M is energized in the following cir-'- cuit: Earth, contacts 82, 83, release relay M, otl' normal contact 84 (closed at the first lifting step of the group selector), battery. The numerical switches at exchange A- which have been set b Y impulses transmitted from the sender in the operators position, released and are immediately available or another connection. In addition to the abovedescribed circuit changes, the auxiliary relay N brings about i the following circuit changes. At cont-act. 84 the testrelay P of-the switch MLW is connected to the test wiper 85. By opening contact 264 and closing contact 86, the circuit of relay V isprepared by connecting it to contact =87 of the impulse receiving relay '105 A,. By opening contact 88 and closing contact 89, the rotary magnet D, is energized as follows: Battery, contact 263, rotary magnet D contacts 690, 89, 91, earth. The Wipers of switch MLIV are moved on until they reach a free third group selector III GIV, these selectors being connected to the last contacts of the row. Thereupon the fol? lowing circuit for test relay P is completed:

Battery, contact 90, windings II' and I of re- I lay P contact 84, wiper 85, conductor 92, contact .93, relay 0,, earth. The relays P, and C, respond. Relay P, at contact 91 3 opens the clrcuit of the rotary magnet D,,

at 94 short circuits its high resistance \vind- I ing I, and at'95 prepares the circuit for the switching relay 1*. Relay C, at contact 96 connects up the relay A The impulses for setting the third group selector are repeated by the relays A and A to the lifting magnet H Relay A is intermittently deenergized in the following circuit: Battery, contacts 87, '86, relay V conductor 97, contact 96, relay A earth. It should also be mentioned that relay A at contact 1953 en- 9' contact 108,'which is opened at the ergizes the retardation relay V, and at con: tact 99 closes, upon each energization the following circuit for the lifting magnet H Earth, contacts 100, 99, relay V lifting magnet H shaft contact" 101, battery.

The third group selector III GWV is set on a free final selector LIV in the same manner as the first group selector I GVV was set on a second group selector II GIV. When a free final selector Ll/V has been found, the relay A is energized over contacts 102, 103, 104. and the spcaking',lead. At contact 105 it connects up the retardation relay V, which at contact 106 closes the locking circuit for relay 0,, which was prepared at 107, and thereby renders this relay independent of the off normal first lifting step of the selector.

The final selector is set in known manner. At. the termination of the last train of impulses for rotating the final selector LIV onto the required subscribers line, relay A, remains deenergized and conse uently relay V, deenergizes, which closes t e following circuit: Earth, contacts 109, 95, switching relay F, wiper 110,. conductor 111, contacts 112, 113, blocking relay S, contacts 114, 115, battery. The blocking relay S closes its contacts 116 and then by opening its contact 11% connects itself to a locking circuit independently of contact 115. The group blocking relay GrS is energized over contact 116 and by opening the contact 115 prevents other S relays beingenergized. The relay S at contact 117 connects battery over relay (ir to the incoming lead a, of the busy third group selector III GIV. Relay F short circuits resistance 13 as follows: Battery, contacts 118, 119, 120, relay C, c-wiper of the second pro-selector II VVV, contact 12, winding II of relay T and thence to earth over the (1 lead and c wiper of I VIV. The current over the c-wipers of the second and iii-st pre-selectors is thereby increased and the marginal relay U responds at. the second pro-selector. Relay U connects up its winding II over its contact 121, and the contact of the cut off relay T and by opening the contact 12 and closin the contact 123 switches over the out o relav T from wiper 0 to wiper 0, so that relay T is de-energized. The calling relay R is again connected up over contact 3 and the locking circuit for winding 2 of the slow acting relay U is maintaii'ied over contact 124; which is parallel to contact 122. The rotary magnet I) is again cmineeted up over contacts 16, 10, and thcsecond )IQ-SQIGCtOl ll VW now hunts for the thir group selector I II GVV that has been taken into use by the auxiliary switch MLW. It has already been mentioned that battery has been connected to the incoming lead 0 at only one of the free third group selectors III GW,

so that the second pro-selector II VW can only set itself on this roup selector. When it has done so, the fol owing circuit is completed: Earth, contact 11, windingsjI and II of relay T contact 123, wiper c of the second pro-selector II VW, 0' lead, relay G, contactllT, battery. Relay T effects the same circuit changes as in the case when a free trunk line is taken into use on a subscriber taking off his receiver.

Moreover, by closit maintains energized the U and thereby connects itself'to wiper c for the duration of the conversation. At the third group selector III GIV the relay G operates and at contact 124 closes a locking circuit which has been prepared at. contact 12!. It furthermore opens contacts 113 and 93. Relays C and S and thereby also the grou lay GrS are deenergized, causing the removal' of the engaged condition at the other group selectors. Relays F and P at the switch MLW are deenergized. The rotary magnet D, is energized oy'er contact 91 as follows: Earth, contacts 91, 89, 690, rotary ing contact 122, switching relay magnet D contacts 126,127, battery. Theswitch MLW is normal position,

rotated until it reaches its whereupon the contacts 72 and 127 are opened. Thus the operating circuit of the operating magnet D, and the locking circuits'of the relays O and N are opened. At this time the oif normal contact 15 is also closed so that the trunk line can again be taken into use by asearching second pro-selector. 1

After the second pro-selector II VIV has been set on the third group selector III GIV, the bridge relay A is energized, which cuts in the releasing rela V by closing the contact 128 lying paralleIto contact 198. At the end of the conversation, when the circuits of relays A and V have been opened, the release magnet M is cut in at contacts 129 and 130. The circuit for relays P and (I, at the final selector LIV is at the same time opened at contact 131. The releasing of the final selector LIV can take place in any desired manner.

Relay B, Fig. 2, part 2, connected to the trunk line is energized when the connection remains set up over the trunk line and the wanted subscriber answers. Relay B then switches the speaking leads through at contacts 132 and 133. When the connection is established the operators position, connected up at the exchange A by the service selector DIV, is released in the following manner.

After all the trains of impulses have been transmitted, relay E is energized over contact 134, and at its contact 135 connects up a relay W, which remains energized for the duration of the conversation over its contact 136 and contact 28 of relay 0,. Relay W opens a further point in the circuit of the magnet D at contact 31, and at contact. 31

blocking reopens the circuit of relay T whereupon relay T falls back and disconnects the wipers of DW.

Figure 3 shows the arrangement of the selectors in a full automatic telephone system, in which large capacity group selectors are used. It is assumed thatthey each have 20 groups of contacts. If the subscriber 'l requires connection with thesubscriher T whose 'nurnl'ier is assumed to be 25632, the first and second pro-selectors are set on the trunk line 'VL, in known manner. The registers for storing up impulses are then opcrated over a service selector DW. When all the impulses haveheen stored up, the numerical switches are operated. It will he assumed that the following arrangement is adopted. It a selector is set on a contact group having unevennumbers, the next selcctor will-be set by a train of impulses, comprising a number of impulses, which correspond to the impulses sent out by the calling subscriber. If, however, a numerical switch is set ona contact group bearing an even number, the next numerical switch will be set on a contact group which is reached by 10 plus a impulses, n representing the number of impulses sent out by the subscriber. In the present example the first group selector I GIV is set on the second group, then the second group selector II GWon the fiftccntli group. the third group selector III group.

GIV on the sixth group, and since the latter is again a group with even numbers, the final selector LIV is set on the thirteenth The first digits of the subscribers connected to the small exchange AU containing the calling subscriber, are characterized by 35. Hence for a call tot-his exchange the first group selector I GIV is set on the third (ill contact group and the second group selector Il GIV on the fifth group. whereupon a local third group selector III GIV is connected in a similar manner as in the case of Figure 1 by means of a switching device, and the group selectors. which have already been set, are released. \Vhen the setting has been completed the subscribers T and T converso over the first and'second pro-selectors I YIV. II V'W, the trunk line VL,,, the third group selector III GIV and the final selecfol 11 V.

The method of setting up a connection between two subscribers of the same small exchange will now be explained with reference to Figures 4 and '1.

When the suliiscriber T originates a call, the first and second pro-selectors select the trunk. line VI as previously described with reference to Figure 2. Relays A and C associated with the trunk line respond, the latter over contact 155. Relay C at contact 153 prepares its locking circuit, opens contact 156 and by closing contact 157 energizes relay (1,, which is connected to the c-lead at the exchange A. Relay 0,. is not energized same manner as in Fig. 2.

- by this current and can only be energized v when resistance 158 18 short circuited m ths a The relay A, which was energized by the current over the subscribers loops,-has energized over contact 159 the retardation rclay V which, by closing contact 154, has completed the locking circuit for relay C independently of the off normalconta'ct 155. The impulse contact 163 is connected to the a lead of the 'trunkline over eontacts 161 and 162.

The manner of connecting up the register. in the exchange A will now be described. The driving magnet D of the service selector DW, Fig. 4., part 1, is energized as follows: Earth, contacts 16 1, 165, 166, ,rotary magnet D. contacts 167 168, battery. When the service selector DW findsthe trunk line, the following circuit is completed: Earth, contacts 169, 170, relay F, wiper 171 of the service selector DW, windings II and I of relay P contact 172, battery. Relays F and P respond, F opens at contact 166 the energizing circuit for the rotary magnet D which moreover opened by relay P, at contact 168, and then closes its contact 173. Relay P ing I of relay P at contact 174 and closes contact 175. The following circuit is thereby completed: Earth, contacts 163, (Fig. 4, part 1, relay A) 161, 162, a lead of the trunk line VL,, conductor 176, contacts 177. 173, wiper 178 of the service selector .IWV, contacts 175 and 179,.retardation relay V contact 180, impulse receiving relay A,, battery. Relays A, and V energize, and re-- lay V, closes its contacts 181, 182, 183. The circuit for the driving ma ets D,-D,, of the five registers Reg. 1-- is prepared at contact 181. Contact 182 connects up the holding magnets HM, of the impulse storing registers Reg. 1-V, and the holding magnets HM,, of the registers Reg. XI-- XV which transmit the impulses to the selectors. It is assumed that the registers comprise switching devices having a pawl which engages the cog wheel when a locking 1nagnet is energized, whereupon the switching.

device can be moved step by step by an electromagnet. The switchlng devices can, for

marks engaged the found trunk line by 9 short circuiting the high resistance wind 

